206 Section at Battle. 



graphical order of these strata, in this area, see diagrams, 

 Nos. 71, 72, and 73, pp. 337-343. 



In this area, near Battle, the lowest strata rise to 

 the surface, being the fresh- water Purbeck Limestone, 

 interstratified with beds of clay. For long in this area 

 they were known as the Ashburnham Beds, but the 

 fresh -water shells and other fossils found in them during 

 the progress of the experimental boring already men- 

 tioned, clearly proved them to belong to the Purbeck 

 Series. They are there about 180 feet thick, and over- 

 lie about 110 feet of shales, somewhat sandy, with 

 chert, which may perhaps represent the Portland beds. 

 In the Purbeck strata, at a depth of i 30 feet, 35 feet 

 of gypsum more or less pure were penetrated, a mineral 

 much more sparingly developed in the lower strata of 

 the Isle of Purbeck, and which I consider indicates, 

 that these strata were not laid down in the sea, but 

 probably in a lagoon temporarily separated from the 

 main current of the river. Beneath the so-called Port- 

 land beds about 921 feet of Kimeridge Clay were 

 pierced, followed by 985 feet of Coral Eag and Oxford 

 Clay, when, for want of funds, this interesting expe- 

 riment was stopped at a total depth of 1,906 feet 

 from the surface. 



The HASTINGS SANDS and WEALD CLAY are almost ex- 

 clusively fresh-water beds, and must be considered as a 

 continuation of the deposits formed at the mouth of the 

 great river, which commenced with the deposition of 

 the Purbeck limestones and shales. The name Wealden 

 applies to the whole group above the Purbeck rocks, 

 and the term originated from the circumstance that 

 these fluviatile beds are largely developed in the Weald 

 of Kent and Sussex. Their true character was first 

 discovered by Dr. Man tell. As a whole, the Hastings 



